Telegraphic synchronizing system



Jan. 19, 1960 E. N. DINGLEY, JR

TELEGRAPHIC SYNCHRONIZING SYSTEM Filed July 1, 1954 United States Patent() 1 TELEGRAPHIC SYNCHRONIZING SYSTEM Edward Nelson Dingley, Jr., Arlington, Va.

Application July 1, 1954, Serial No. 440,877

5 Claims. (Cl. 178-17.5)

(Granted under Title 35, U.S. Code (1952), sec. 266) The invention described in the following specication and claims may be manufactured and used by or for the Government for governmental purposes without the payment tome of any royalty thereon.

My invention relates broadly to means by which printing telegraph signals having an irregular character rate may be introduced into and transmitted by a synchronous printing telegraph system wherein the character rate is very constant.

My invention relates chiey to means by which printing telegraph signals originated at an irregular character rate by a keyboard-operated transmitting distributor or originated at a regular character rate during random time intervals by punched-tape transmitter-distributor, may be introduced into and transmitted over a printing telegraph system wherein the line-transmitting apparatus and the line-receiving apparatus are maintained in synchronism and in iixed phase relationship, dispite noise or circuit-outages, by the use of frequency (rate) standards at each terminal. l

One of the objects of my invention is to provide a device that will permit keyboard operation over synchronous printing telegraph circuits.

Another object of my invention is to provide a simple, dependable, and relatively inexpensive printing-telegraph start-stop extensor. Y

Other and further objects of my invention will be understood from the following specification and claims.

The drawing illustrates diagrammatically one embodiment of my invention.

Referring to the drawing, the output distributor comprises an inner ring of electrically conductive segments insulated from each other, an outer ring 11 of electrically conductive segments insulated from each other and insulated from ring 10, a brush arm having two ends designated by symbols 12 and 13, a pair of electrical brushes 12 and 12" electrically joined together and mounted on end 12 of brush arm 1213 which make rubbing electrical contact with rings 10 and 11 respectively, an electric motor (not shown) which through the means of suitable gears (not shown) and a friction clutch (not shown) rotates the brush arm 12-13 at the velocity of one-half revolution in TR milliseconds, a stop lever 14 capable of engaging end 12 or end 13 of brush arm 12-13 so as to stop the rotation of said brush arm when the brushes are in the position depicted in the drawing or diametrically opposite thereto, and a start-magnet 15 which when energized retracts the stop lever 14 and permits the brush arm to rotate. Timing means for the magnet are indicated but not shown in detail as conventional devices may be used.

The start magnet 15 is energized during an interval of approximately T/7 milliseconds once each T milliseconds.Y The time TR required for a half-revolution of-the output distributor brush arm is chosen so that TR is approximately equal to 8T/9 thus permitting the brush arm end 12 or 13 to strike the stop lever 14 and remain 2,921,978 Patented Jan. 19,` 1960 at rest for approximately T/9 milliseconds until the next electrical pulse is applied to start-magnet 15.

In rest position as shown in the drawing (or diametncally opposite thereto) the brushes of the output distributor rest on non-energized (Rest) segments of the inner and outer rings; however, shortly prior to their arrival at rest position they had connected negative battery from the outer ring Stop segment to the inner ring segment 17 or 17', through the jumper 17a or 17b shown connecting segment 17 to the long segments 10b and 10a of the inner ring, to terminal 18-1 of polar relay 18, out terminal 18-6, through resistor 19 to positive battery. Current owing in the aforesaid direction through terminals 18-1 and 18-6 causes the armature 18-7 t0 engage spring 18-4 thus connecting negative battery from spring 18-4 through armature 18-7 through resistor 24, to terminal 1S-2, out terminal 18-5, through resistor 22 to positive battery and also thus connecting the same negative battery to terminals 21-1 and 21-2 of polar relay 21, out terminals 2l-6 and 21-5, through resistor 22 to positive battery. Current owing in the aforesaid direction through 18-2 and 18-5 of relay 13 constitutes a holding current which holds the armature 18-7 in close contact with spring y18-4 even though the current through terminals 18-1 and 18-6 is interrupted by the brushes of the output distributor coming to rest on the non-energized segments as shown in drawing. Current owing in the aforesaid direction through the windings of relay 21 holds the armature 21-7 in close contact with spring 21-4 thus closing the circuit of the output line.

Upon the release of the output distributor brush arm 12-13 by stop lever 14, the brushes rotate in a clockwise direction until they engage the leading edge of the Start segment of the outer ring and the leading edge of segment 16 of the inner ring thus connecting positive battery to segment 16, through the jumper shown connecting segment 16 to the long segments of the inner ring, to terminalv 18-1 of polar relay 18, out terminal 18-6 through resistor 20, to negative battery. Current owing in the aforesaid direction through terminals 18-1 and 18-6 of relay 1S causes armature 18-7 to engage spring 18-3 thus connecting positive battery from spring 18-3 through armature 18-7, through resistor 24, to terminal 18-2, out terminal 18-5, through resistor 23 to negative battery and also connecting the same positive battery to terminals 21-1 and 21-2 of'polar relay 21, out terminals 2l-6 and 21-5, through resistor 23 to negative battery. Current ilowing in the aforesaid direction through terminals 18-2 and 18-5 of relay 18 constitutes a holding current which holds the armature 18-7 in close contact with spring 18-3 even though the current through terminals 18-1 and 18-6 of relay 18 is interrupted by the brushes of the output distributor advancing in a clockwise direction to the next pair of non-energized segments of the outer ring. Current flowing inthe aforesaid direction through the windings of relay 21 holds the armature 21-7 in close contact with spring 21-3 thus opening the circuit of the output line and providing the beginning of the required spacing-start pulse of standard teletypewriter code.

The spacing condition of the output line endures until the brushes connect segment 101 of the outer ring to the long segment 16a of the inner ring. The leading edge of segment 101 is spaced from the leading edge of the Start segment by an angle such that the brushes, when rotating-at the velocity of half-a-revolution in TR milliseconds, will require T/ 7.42 milliseconds to travel through the aforesaid angle. Because of slippage in the friction clutch, the acceleration of the brush arm is not iniinite upon its release from the rest position. In consequence and in order that the duration of the start pulse maybe adjusted to be exactly T/7.42 milliseconds, the

.'.y inner ring of the output distributor is designed to be capable of manual rotation through an arc of about six degrees in order that segment 16 of the inner ring, which governs. the. instantof beginning. of. the start pulse,Y may be adjustedv to alesser angular' distance from segment 1.01. ofv the. outer. ring, .thus achieving a start pulse of 177.42 milliseconds duration. despite constant clutch slippage during accelerationof brush arm 1-2-13. Manualf clockwise rotation. of the inner ring (from the extremecounter-clo'ckwise.position shown) through an angle ineXcess ofthe arc Width of segment 17 will place a portion of segments '17 and 17 in radial alignment with portions of the Start segments of the outer ring. In order to obfviatetheundesirable condition which would. result from' suchA juxtaposition, the jumpers 17a'and 17h connecting segments 17 and 17 to the long segments of the inner ring may be removed thus dce-energizing segments 17 a11d.17".Ak Segments. 1 7 and 17 maybe considered asextensio'ns` oflong segments `10 andla, respectively, when their jumpers are connected.

.At a mel/7.42. milliseconds after the beginning of th'elspacing startpulse previously described, the clockwise rotatingbrushes connect the leading edge of segment 101 .to the inner ring and. complete a circuit from the 7 side of Vcapacitor 26 to terminal 18-1 of relay 18, out. of terminal `18-6 and back to the b side of capacitor 26. If capacitor 26 is. uncharged, tonguek 18-7 of relay 18`iwill remain'engaged with its spring 18-3. If Y the a side of..`capa'citorV 26 has a positive charge, the resultant disch'argenof currentthrough terminals 18-1 and `I8`6 Aof relay 18.wil1 reinforce the pressure of tongue lf the a side of capacitor Y Y contactY spring 18-.4 where it will be constrained to remain by the holding circuit previously described. Resis` tor 24 'limits the. holding current to a value sufficiently less than the current through winding 18-1--18-6 "o f relay 18 so `that the. latter signalling current invariably overcomes the eiiect of the. holding current. The arc length ofsegmentllll and of all similar short segments 102-105 and 2014-205 of the outer ring is such thattheduration of`brushcontact therewithis the minimum required to assure proper response of polar relay 18, that'is, approximately T/ZS milliseconds.V The capacitance of capacitors 26 thru 30 and of capacitors 31 thru 35 is chosen such as to assure their complete discharge through winding 18-1-18-6 of relay 18 in T/ 25 milliseconds.

The leading edgesl of: the short segments 101-105 and 201-205of the output distributor.V are spaced from each other by an angle such* thatthe time required for the leading edge of the outer ringbrush to travel from the leadingl edge of one short segment to the leading edge of the next is 177.42 milliseconds. As the brush sequentially makescontact with segments 101-105 or 20L-205,r capacitors 26 through 30 or capacitors 21 through 35 are discharged in sequence through winding 18-1--18-6 of relay18, thus causing the tongue 18-7 of Vrelay 18 (and'consequently the tongue 21-7 of relay 21) to more from spacingtcontact 13-3) to. marking (contact 1S4) in accordance with the positive and negative charges stored on capacitors 26 through 35.v

The leading edgel of the Stop segment of the outer ring of the output distributor is reached by the brush T/7.'42 milliseconds after the passage of the brush over the Aleading edge of segment 105 and there is established a circuit from negative battery on'the outer ring Stop segment to inner ring long segment (either directly or through the. jumper fromsegment 17 or 17' depending on vthe position to which `the inner. ring has been manually rotated), `to terminal '181 of relay 13, out terminal .18-6, through resistor19. and to positive battery. The resultant current ow through the indicated-:windingpf relay. 1,8;

causes the tongue 18-7 to make and maintain contact with its spring 18-4 even after the brush has advanced beyond the Stop segment and come to rest upon the unenergized Rest segment. In consequence of this action, the tongue 21-7 of relay 21 is caused to make and maintain contact with its spring 21-4, thus closing the output line and producing the markingrstop signal of a standard teletypewriter signal.

The Start segments ofthe output distributor are always at positive potential and Ythe'Stop segments are always at negative potential. In consequence, the output distributor causes the contacts of relay 21Y to key the output circuit with standard 7.42 unit teletypewriter startstop signals. When capacitors 26-35 are not charged, relay 21rernain`s in a spacing condition between the end of the start pulse and the beginning of the stop pulse. ln conseuqence, the output distributor sends the blank teletypewriter character at the rate of 60,000/T charactersiper minute Whenever the capacitors 26-35 are notfcharged.-

The shaft 12s of the bnush arm 12-13 is provided vwith a cam 36 anda carn operated switch 37--38-39 arranged so that-'the tongue 37 engages spring 38 during the clockwise rotation of brush arm 12 between segments 203 and 103, and so that tongue 37 engages spring 39 during the clockwise rotation of brush arm 12 between segments 163 and 203. The-illustration includes a schematic representation of a tape reading transmitter-distributor 40 of known type (Teletype Model 14XD) and a keyboard transmitter 4l of conventional type arranged to key the tongue 42-7 of relay 42l -in the usual manner. These transmitters are not partof this invention but are normal ancilliary apparatus for providingrthe input signal.

The input `,distributor depicted/comprises an inner ring 43 comprisingV two electrically conductive segments 43 and 43" insulated from each other, an outer. ring cornprising fourteen electrically conductive segments insu lated from each other vand insulated vfrom the inner ring, a bnlsh arm 44, two electrical brushes 44- and 44 elec4 tri'cally joinedtogether. and v-mountedf on brusharm 44 which.` brush'es-'1nal erubbingV electrical contact with the inner and outer rings, an electric motor (not shown) which-throughthe means ofi suitable gears (not hsow-n) and'. a` riGtiOncIutchr (not shown.) rotates fthe brush arm 44v at: the` velocity of.k onerevolution' in -Ts milliseconds, a stop lever 45 capable of engaginge'end 440i?V the-brush arm's0--as-tostopits'rotation when the brushes are in thefposition. shown, 1 and-:astart-magnetv 46 which when energizedretracts the stop lever 45- and permits the brush arm torotate.

When'no teletypewriter signals are originated by the keyboard *or otherinput devices, tongue 42-7 of relay 4Z-engagesY negative battery at its spring 42-4. This negative 'potential is conducted from the inner ring 43 thru the brushes VAto the outerfring Rest segment, through start magnet .A6-and back to the same negative battery. There being no potential difference, magnet 46 is not energizedandl stop lever 45 prevents brush arm 44 from rotating; Whenever a code character is received by relay 42.,l the first element of the signal causes tongue 427 of relayy 4Z toengage positive potential at spring 42-3. The resulting Vpotential diierence operates magnet 46 and releasesl brushmarm 44 which starts to rotate at the velocity ofone revolution Vin-TS milliseconds.

The'speedof the keyboard transmitter and of `the tape transmitter Vor other inputdevice are adjusted so as to send one complete character in t milliseconds wheret isapproximately2% greater thanV the time T in Ywhich the.Y output relay 21 sendsl one` complete character, or Vz -1Y.O2T. Thetime 'IS-,required fora revolution of the input' distributor. brush arm Mis-chosen such-that Ts is approximately equalto 8t/ 9 'thus permitting-the brush arm. to `strike the .stop lever 45 andremain at rest` for aty least l/9 milliseconds until the next electrical pulse is applied to start-magnet 46.

The center of segment 301 of the outer ring of the input distributor is located at an angular position from the rest position of the brushes so that the center of the brushes will reach the center of segment 301 in the time l.5t/7.42, that is, in the center of the first selection element of the received character. The angular Width of segments 301 through 305 of the input distributor is such that the duration of contact with the brush is approximately t/25 milliseconds. The values of resistances 47 and 48 yare suiciently low to insure that each of capacitors 26-35 will be fully charged in less than the t/25 milliseconds required for the brushes to sweep across segments 301-305 The centers of segments 301 thru 305 of the input distributor are spaced apart by an angle equivalent to t/7.42 milliseconds at the prescribed brush velocity. In consequence, the brush will sequentially connect ring 43 of the input distributor (and tongue 42-7 of relay 42) to segments 301 thru 305 of the outer ring of the input distributor so as to sample the exact center of each selection element of each input character, The position of stop lever 45 with respect to the rings of the input distributor is adjustable to provide a range adjustment.

The shafts 44s that rotates brush arm 44 is provided with a cam 49 which engages spring 52 with spring 51 for a period of approximately t/25 milliseconds immediately following the release of brush arm 44 by stop lever 45. For the remainder of the cycle, spring 52 engages spring 50 whereby capacitor 53 receives a charge through resistor 54 from positive battery. Whenever the brush arm 44 of the input distirbutor starts from its rest position, cam 49 causes capacitor 53 to discharge by way of springs 52 and 51 to spring 37 and thence through spring 38 and terminals 56-2 and 56-5 of relay 56 to negative battery, or by Way of springs 37 and 39 through terminals 56-6 and 56-1 of relay 56 to negative battery.

As previously stated, springs 37 and 39 will be engaged if the output distributor brush arm 12 is in a position more clockwise than segment 103 and less clockwise than segment 203. In this circumstance the starting of the input distributor will cause capacitor 53 to discharge (as previously described) a posi-tive charge into terminal 56-6 of relay 56 and cause tongue 56-7 to engage its spring 56-4 thus applying a holding potential from positive battery thru resistor 57 to terminal 56-6 and thus also applying positive battery through resistor 58 to the magnet of relay 59 and thence to negative battery. The energin'ng of relay 59 connects segments 301 through 305 of the input distributor to capacitors 26 through 30. This connection is initiated at the time that the brush arm 44 of the input distributor starts to rotate and the connection is completed before brush arm 44 reaches segment 301. If this connection is initiated as the brush arm 12 of the output distributor is just leaving segment 103, the positive and negative charges representing the selection elements of the character which is entering the input distributor will be stored in sequence on capacitors 26-30 and the resulting voltages will be applied to segments 101 thru 105 in sequence at a rate which never overtakes brush arm 12 because the Velocity of brush arm 44 is approximately 2% less than the velocity of brush arm 12. The character thus stored in capacitors 26-30 will be read out from segments 101-105 sequentially beginning with the instant when brush arm 12 completes approximately 3%1 of a revolution (in 1.5T milliseconds) and makes contact sequentially with segments 101 thru 105 thus discharging capacitors 26--30 and causing the discharge current to operate polar relay 18 in accordance with the polarity of the selection elements stored in capacitors 26-30; the convention being that a positive charge entering terminal 18-1 of relay 18 causes tongue 18-7 to engage spring 18-3.

If brush arm 12 is just approaching segment203 when the input distributor starts, the charges representing the input selection elements will be stored in capacitors 26-30 as before, but they will be read out from segments 101-105 sequentially beginning with the instantwhen brush arm 12 completes approximately 1/1 of a revolution (in 0.5T milliseconds) and makes contact sequentially with segments 10i-105. The 2% speed differential between distributor brush arms is insuicent to allow brush arm 12 to overtake the energizing of segments 101-105.

If brush arm 12 is in a position more clockwise than segment 203 but less clockwise than 103, spring y3.7 will be engaged with spring 38 and the starting of theinput distributor will cause capacitor 53 to discharge (as previously described) into terminal 56-2 of polar relay 56 and cause tongue 56-7 to engage spring 56-3 thus applying a holding current from positive battery thru resistor 55 to terminal 56-2. The motion of tongue 56-7 from spring 56-4 to spring 56-3 also removes positive battery from relay 59 and causes the 5 tongues thereof to connect segments 301-305 of the input distributor to capacitors 31-35 respectively. This connection is initiated at the time that the brush arm 44 of the input distributor starts to rotate and the connection is completed before brush arm 44 reaches segment 301. If this connection is initiated as the brush arm 12 of the output distributor is just leaving segment 203, the positive and negative charges representing the selection elements of the character which is entering the input distributor will be stored in sequence on capacitors 31-35 and the resulting voltages will be applied to segments 201 thru 205 in sequence at a rate which never overtakes brush arm 12 because the Velocity of brush arm 44 is approximately 2% less Vthan the velocity of brush arm 12. The character thus stored in capacitors 31-35 will be read out from segments 201-205 sequentially beginning with the instant when brush arm 12 completes approximately :A of a revolution (in 1.5T milliseconds) and makes contact sequentially with segments' 201--205 thus discharging capacitors 31-35 and causing the discharge current to operate the tongue 18-7 of polar relay 18 as previously described.

If brush arm 12 is just approaching segment 103 when the input distributor starts, the charges representing the input selection elements will be stored in capacitors 31-35 as before, but they will be read out from segments 201-205 sequentially beginning with the instant when brush arm 12 completes approximately 1A of a revolution (in 0.5T milliseconds) and makes contact sequentially with segments 201-205. The 2% speed differential between distributor'brush arms is insucient to allow brush arm 12 to overtake the energizing of segments 201-205.

If capacitor 53 discharges (by reason of the starting of brush arrn 44) at a time when spring 37 is transiting between springs 38 and 39, that is, when brush arm 12 is in the region of segment 103 or of segment 203, part of the discharge may enter terminal 56-6 of polar relay 56 and the other part may enter terminal 56-2. In this circumstance it is immaterial whether the discharge of capacitor 53 causes tongue 56-7 to remain in its former position or to transit to the opposite position because when brush arm 12 is in the region of segment 103 or of segment 203, an input character may be stored in capacitor banks 26-30 or 31-35 indiscriminately. In one case the stored character will be read out beginning at an instant approximately 0.5T milliseconds later; in the other case, the stored character will be read out beginning at an instant approximately 1.5T milliseconds later. In this invention the combined action, as described, of cam 49 and its contact springs, of cam 36 and its contact springs and of polar relay 56, is such the live tongues of relay 59 will always be connected to a discharged bank of storage capacitors prior to the application to that bank of capacitors of the rst charge representing the rst selection elcmerit'ofn-input character, without regard toY the instant `oftirne'lwhen .that irstselection elementr is received;

Vacters at the rate of 60,00'0/t` characters per minute and that' thiestart'magnet 15 of the output distributor is pulsed at-therate'of 60,000/ T pulses per minute (t=l.02T). In consequence, the output distributor will gain in phase over the input distributor byV onev character after every T/(t-T') :N "characters at which time Vthe cooperative action of cams 49 and 36 will cause two successive input characters to be stored in the same'capacitor bank 26-36 (or in.31-'-35) instead. of in the capacitor banks alternately.` AsV a" resul-t, one of the capacitor banks is uncharged' during one passage of brush arm 12 over the outer ring shortsegments associated with that capacitor bank-and'tlere is inserted'in the output circuit a code blank (space, spaces, mark) between the aforesaid twoiinpu't characters. In the foregoing, N may compute tol be a whole number NW plus a fraction of a character Nf. The number vof voutput characters in the first sequence preceding ablank, will beNwcharacters and the fraction of a'charactervNfV will remain in storage. Each succeeding sequence of output characters will comprise Nw. characters until the summation ofthe fractional portions in storage add to one Vcharacter (possibly plus Va fraction) atlwhich timefthe sequence of output characterswill contain Nw-l-l characters. i

- WhenV the input devices are quiet andno code characters-are being delivered to the input distributor, the output distributorgcaus'esA relay 21 to key` the output line with a continuous sequence of blanks derived from the fact that whenv the brushes of the output distributor engageeach 'permanentlynegativestop segment, the tongue 21-7 of 'output relay 21` closes and maintains closure of the output line until'said' brushes engage the next following permanentlyl positive start segment whereupon relay 21 opens the output Iline and maintains this open condition (there being no charge on capacitorbanks 26-30 and 31a-35) until the brushes-engage Vthe next following permanently negative stop segment. Under the indicated conditions, brush arm 44 and cam 49 remain at rest; capacitor 53 is Vnot discharged into relay 56 and, in consequence, relays 56and59 remainV in the'positions they had previously assumed;

The arrangement'of the'drawing and the foregoing description have been solely, for illustrative purposes. There are many possible variations of the individual circuits and components that maybe utilized to practice my, invention. In particular, it is noted that all of the functions performed by the distributors; storage capacitors (storage cells), camsV (timers) and switches, are achievable through the use of electron-tube circuits, transistor circuits, bi-stable magneticl circuits, and other electronic devices all of which are well Vknown to those skilled inthe art. For the true scope of the invention, therefore, reference should be had to the appended claims.

I claim: t

1. In an apparatus of the nature described, an input distributor including an array of contacts, brush means and means for driving the same over said contacts, and an output lline for each contact, an output distributor including a first group and a second group of contacts each homologous to the array of said input distributor, second brush means and means for driving the same to traverse in succession' the; contacts. off-said rst group and then in succession the contacts'of; said second group, means for' connecting the contacts ofy said input distributor to the contacts of said output distributor group by group including timing means operative to select said first group for such connection if its contacts have been at least substantially half traversed by said second brush meansand if saidsecond group has not been substantially more than half traversed.

2. The invention of claim 1 further characterized in that said means for driving said second brush means drives the same to traverse each of said vfirst and second groups of contacts slightly faster than said first mentioned brush means is driven over its array of contacts.

3. The invention of claim l further characterized in that said timing means includes a rotatable cam, a switch operated thereby, and means associated with said second brush driving means for driving saidcam to operate said switch. Y

4. In an' apparatus of the nature'described, an input distributor including an array of contacts, bursh means for sweeping the same, an output distributor comprising Vtwo arrays of contacts each homologous to the array of said input distributor, means for selecting one of said two last mentioned arrays for connection with said fu'st mentioned array includingV a group of capacitors for each of'said last mentioned arrays, a multiple contact switch wherein the contacts have normal positions for completing circuits to one of said groups of said capacitors and other positions for completing circuits to the other of said groups of capacitors, electrically energizable means for changing the positions of said contacts, means for energizing said last mentioned means including a source of current, attwo-position switch having a normal position and a second position, and means actuated by said' input distributor for causing said last mentioned switch to assume its said other position upon initiation ofxnovementof said first mentioned brush means.

5. In an apparatus of the nature described, the cornbination of means vfor providing sequences'of impulses the sequences being n impulses in length the intervals between the sequences being of unpredictable lengths, an outputdevice including a first group and a second group each of n memory elements for storing impulses and means for scanning said elements-successively at a substantially constant rate and at substantially constant intervals thereby to derive any impulse stored therein, means for connecting said first mentioned means to said first groupV of said memory elements for storing impulses therein after that group has been at least substantially half-scanned and before said second group of said memory elements has been more than substantially half-scanned, and means for connecting said first mentioned means to said second group of said memory elements after said second group of memory elements has been at least substantially half-scanned and before said first group of memory elements has been more than substantially halfscanned.

References Cited in the file of this patent UNITED STATES YPATENTS 1,399,997 Rainey Deo-13, 1921 1,645,805 Dowd Oct. 18, 1927 1,874,664 Ver-nam Aug. 30, 1932 1,881,453 Franklin Oct. 1l, 1932 2,284,680 Potts- June 2, 1942 

